diff --git a/mphys/network/remote_component.py b/mphys/network/remote_component.py
index 77fcbec7..b0468b4a 100644
--- a/mphys/network/remote_component.py
+++ b/mphys/network/remote_component.py
@@ -446,6 +446,18 @@ def _add_objectives_from_baseline_model(self, output_dict):
                 )
                 self.derivative_coloring_num += 1
 
+    def _lower_bound_used(self, bound):
+        if hasattr(bound, "__len__"):
+            return (np.array(bound) > -1e20).any()
+        else:
+            return bound
+
+    def _upper_bound_used(self, bound):
+        if hasattr(bound, "__len__"):
+            return (np.array(bound) < 1e20).any()
+        else:
+            return bound
+
     def _add_constraints_from_baseline_model(self, output_dict):
         for con in output_dict["constraints"].keys():
             self.add_output(
@@ -472,9 +484,10 @@ def _add_constraints_from_baseline_model(self, output_dict):
                         ),
                     )
                 else:
-                    if (
-                        output_dict["constraints"][con]["lower"] > -1e20
-                        and output_dict["constraints"][con]["upper"] < 1e20
+                    if self._lower_bound_used(
+                        output_dict["constraints"][con]["lower"]
+                    ) and self._upper_bound_used(
+                        output_dict["constraints"][con]["upper"]
                     ):  # enforce lower and upper bounds
                         self.add_constraint(
                             con.replace(".", self.var_naming_dot_replacement),
@@ -491,8 +504,8 @@ def _add_constraints_from_baseline_model(self, output_dict):
                                 else None
                             ),
                         )
-                    elif (
-                        output_dict["constraints"][con]["lower"] > -1e20
+                    elif self._lower_bound_used(
+                        output_dict["constraints"][con]["lower"]
                     ):  # enforce lower bound
                         self.add_constraint(
                             con.replace(".", self.var_naming_dot_replacement),
diff --git a/mphys/network/server.py b/mphys/network/server.py
index 866fb857..472823ba 100644
--- a/mphys/network/server.py
+++ b/mphys/network/server.py
@@ -276,6 +276,18 @@ def _apply_reference_vals_to_desvar_bounds(self, desvar_dict):
             )
         return desvar_dict
 
+    def _lower_bound_used(self, bound):
+        if hasattr(bound, "__len__"):
+            return (bound > -1e20).any()
+        else:
+            return bound
+
+    def _upper_bound_used(self, bound):
+        if hasattr(bound, "__len__"):
+            return (bound < 1e20).any()
+        else:
+            return bound
+
     def _apply_reference_vals_to_constraint_bounds(self, constraint_dict):
         if (
             constraint_dict["adder"] is None and constraint_dict["scaler"] is None
@@ -287,13 +299,13 @@ def _apply_reference_vals_to_constraint_bounds(self, constraint_dict):
                     + constraint_dict["ref0"]
                 )
             else:
-                if constraint_dict["lower"] > -1e20:
+                if self._lower_bound_used(constraint_dict["lower"]):
                     constraint_dict["lower"] = (
                         constraint_dict["lower"]
                         * (constraint_dict["ref"] - constraint_dict["ref0"])
                         + constraint_dict["ref0"]
                     )
-                if constraint_dict["upper"] < 1e20:
+                if self._upper_bound_used(constraint_dict["upper"]):
                     constraint_dict["upper"] = (
                         constraint_dict["upper"]
                         * (constraint_dict["ref"] - constraint_dict["ref0"])
@@ -306,12 +318,12 @@ def _apply_reference_vals_to_constraint_bounds(self, constraint_dict):
                     - constraint_dict["adder"]
                 )
             else:
-                if constraint_dict["lower"] > -1e20:
+                if self._lower_bound_used(constraint_dict["lower"]):
                     constraint_dict["lower"] = (
                         constraint_dict["lower"] / constraint_dict["scaler"]
                         - constraint_dict["adder"]
                     )
-                if constraint_dict["upper"] < 1e20:
+                if self._upper_bound_used(constraint_dict["upper"]):
                     constraint_dict["upper"] = (
                         constraint_dict["upper"] / constraint_dict["scaler"]
                         - constraint_dict["adder"]